Chapter 1, Problem 5E

Program Plan Intro

String functions:

The string functions and their purpose is shown below:

• The function “strcpy(s1,s2)” copies string “s2” into “s1”.
• The function “strcat(s1,s2)” concatenates string “s2” on end of “s1”.
• The function “strlen(s1)” returns length of “s1”.
• The function “strchr(s1,ch)” would return a pointer to first presence of character “ch” in string “s1” .

Explanation of Solution

//(b)strcmp function

The function “strcmp()” compares two strings. It takes header pointer of two strings as function arguments, it checks until the string reaches null and compares both strings by comparing each character at corresonding position ...

Explanation of Solution

//(c) Strcat function

The function “Strcat()” copies data of “s2” to “s1”. To do so, it first reaches end of the string “s1” using recursive calls “Strcat(++s1, s2)”...

Explanation of Solution

//(d) Strchr function

The function “Strchr()” searches for a particular character in string. It iterates through character array and compares each character with search character, if it matches then the index of match is returned.

char* Strchr(char *s, char ch)

{

/*It checks for each character in string and compares it with that of the search string until the     character array reaches null or it becomes empty. If a match is obtained, then store index of match*/

for ( ; *s != ch && *s != '\0'; s++);

  //Return index of matched character

  return *s == ch ? s : 0;

}

The main function defines two character array and tests the functions “Strlen()”, “Strcmp()”, “Strchr()”, “Strcat()” and displays the final result based on the return values of each functions

int main()

{

//Declare the variable

int ret;

//Declare character arrays

char str1[100] = "Drowning";

char *str2 = "Boat";

//Declare pointer of string

char *pch;

//Declare variables

int length ;

//Call the function "strlen()" and store the return value

length = Strlen(str1);

//Display first string

cout<<"String1: ";

puts(str1);

//Display second string

cout<<"String2: ";

puts(str2);

//Display the length of first string

cout<<"\nLength of String1 :"<< length;

//Call the function "Strcmp()" and store the return value of function

ret = Strcmp(str1,str2);

If return value is less than 0, then “String1” is less than “String2”. If return value is greater than 0, then “String2” is less than “String1”, else “String1” equals “String2”.

if(ret < 0)

{

  //Display the result

  cout<<"\nString1 is less than String2";

}

If return value is greater than 0, then “String2” is less than “String1”

else if(ret > 0)

{

  //Display the result

  cout<<"\nString2 is less than String1";

}

If “String1” equals “String2”, display the equal message

//"String1" equals "String2"

else

{

  //Display the result

  cout<<"\n String1 equals String2";

}

The function “Strchr()” is called with “str1” and search character “r” as argument, function’ sreturn value is stored, that is , the value of matched index...